It is known that consumers desire to use cosmetic and personal care compositions that enhance the appearance of keratin fibers such as hair by changing the color of the hair and/or by imparting various properties to hair such as shine and conditioning. The process of changing the color of hair can involve either depositing an artificial color onto the hair which provides a different shade or color to the hair or lifting the color of the hair, such as for example, from a dark brown shade to a medium brown or a light brown shade.
However, there are difficulties presented with obtaining consistent and uniform color on hair when consumers dye or alter the color of their hair. For example, the hair will grow out, creating a visible demarcation line between the regrowth of the roots and the last dye session. Artificial color on hair also has the tendency to fade over time, especially during the shampooing process, resulting in a dull or matte look to the hair fiber. Furthermore, the processing times for hair color compositions vary greatly for undyed virgin hair (not chemically processed hair) and heavily colored or chemically processed hair. The level of skill required to preserve the condition of overly colored and processed hair when applying a fresh coat of hair color while also maintaining a uniform shade of color from root to tip is very high.
It has now been discovered that by providing an acidic hair pretreatment composition comprising at least one film-forming latex polymer, a neutralizing agent, an organic solvent and water, it is possible to form a film or coating on a substrate that has certain desirable properties, such as a protective barrier that will control or slow down the coloration process. Said compositions may be used prior to dyeing to either enhance or reduce the dye penetration into the fiber. Said compositions may also be applied on overly chemically processed hair before coloring or altering the color of the hair in order to preserve the condition of the hair and to also provide a uniform color of the hair from the root to the tip. In particular, the compositions can be used in re-coloring or re-dyeing the hair. Typically, a visible demarcation line at a point along the shaft of artificially colored hair can be observed as new hair grows out from the roots As the hair grows out, the color of the hair from the demarcation line down the length of the hair is generally different from the color of the new hair. Accordingly, the hair pretreatment compositions of the invention, that aid in the uniform distribution of coloring agents onto the hair fiber or in obtaining uniformly colored hair along the length of the hair fiber or in satisfactory gray hair coverage can be useful in increasing the efficiency of hair coloring agents and/or of hair coloring processes.
In addition, applying the acidic pretreatment composition of the present invention onto hair in order to create a barrier or coating on hair may also be useful in highlighting, lowlighting, and bleaching of hair. Such a barrier or coating allows the selective coloration or alteration of the color of portions of hair while leaving other portions of hair unchanged and/or uncolored, resulting in color alterations only in selected portions of the hair. Accordingly, the acidic hair pretreatment compositions of the invention can also aid in achieving a multi-toned or multi-colored or highlighted or lowlighted hair in a more convenient and easy manner.
Surprisingly and unexpectedly, the inventors have discovered that using an acidic pretreatment composition on hair before coloring or altering the color of the hair wherein the composition comprises a film-forming latex polymer, a neutralizing agent, an organic solvent and water resulted in a method for controlling or slowing down the coloration of the hair in order to allow for more uniform hair coloring. The current invention allows for easy and improved coloration of the hair fibers to get a uniform hair color from root to ends of the hair. When applied starting from the visible demarcation line which is generally in the middle of the hair shaft (mid-shaft) down the length of artificially colored hair, the pretreatment composition of the invention will create a barrier or coating on the hair to impede a subsequent hair color altering or hair coloring composition from penetrating into the shaft as fast as it would without the pretreatment composition on the hair.